Mortality following substance use disorder treatment: population-based record-linkage retrospective cohort design


A. González-Santa Cruz 1, 2,

A. Castillo-Carniglia 1, 3,

1 Millennium Nucleus for the evaluation and analysis of Drug Policies
2 Ph.D. student, School of Public Health, Universidad de Chile
3 Department of Public Health, Facultad de Medicina y Ciencia, Universidad San Sebastián, Chile

Background

  • Chile has one of the highest alcohol consumption in the continent\(^{[1]}\) and one of the highest rates of high school cocaine, coca paste, and marijuana use in the Americas\(^{[2]}\)
  • Had over 170% growth in drug-related mortality, 2000 vs 2019\(^{[3]}\)
  • In 2020, 6% of Chileans (12-64) had a problematic substance (alcohol & drug) use \(^{[4]}\)
  • Chilean government funds substance use treatments (SUT) for all with public health insurance (~81% of the population)\(^{[5]}\)
  • There is limited information regarding short-term, medium-term, and long-term mortality risks
  • Analyzing mortality among administrative regions may reveal disparities in post-treatment outcomes
  • Regional data can inform policy and resource allocation

Objectives

To describe the standardized mortality ratios (SMRs) for all adult patients in publicly funded SUT within 2010-2022, along with regional specificities

Methods

Design: a population-based retrospective cohort of adults enrolled in Chilean SUT programs (18-65) with national mortality data (2010-2020).

Analysis plan:
  • Calculated SMRs by comparing observed vs. expected deaths within regions, age groups, periods, and sexes
  • Stratum-specific population estimates obtained from National Institute of Statistics projections\(^{[6]}\)
  • Regional data on substance use from 2020 Chile National Drug Study by National Drug and Alcohol Prevention and Rehabilitation Service\(^{[4]}\)
  • Calculated 95% confidence intervals using Vandenbroucke’s method\(^{[7]}\)


    • Preliminary Results

    Characteristics of SUT patients

    Figure 1: Characteristics of SUT patients

    .

    Standardized mortality ratios for people in SUT, by age group and sex

    Figure 2: Standardized mortality ratios for people in SUT, by age group and sex

    .

    Regional data in quartiles

    Figure 3: Regional data in quartiles

    • The SMR in the SUT population was 15.5 (95%CI 15.0, 16.1) times higher than expected based on the general population.
    • Women aged between 30-44 had a mortality risk up to 29.6 times (95%CI 26.0, 33.5) higher than expected.
    • Regions with high SMRs for men also have high SMRs for women.
    • Ñuble showed some intervals with zero values due to its establishment in 2018.
    • There were regional variations in mortality risks post-SUT.
    • The regional prevalence of problematic substance use does not appear to be related to SMRs.

    Discussion

  • High cumulative mortality risk in SUT patients vs. general population
  • Higher risk particularly among women
  • Largest sex gap at younger ages \(^{[8]}\)
  • Further exploration of substance use’s contribution to elevated risk
  • Mortality risks were higher in areas influenced by ethnic and cultural barriers, discrimination, or geographical isolation, which hinder access to treatment \(^{[9; 10]}\)
  • Future studies should address the causes of these disparities beyond aggregated problematic substance use

    • References

    [1] B. Vicente, S. Saldivia, and R. Pihán. “Prevalencias y brechas hoy: salud mental mañana”. In: Acta bioethica 22 (2016), pp. 51–61. ISSN: 1726-569X. DOI: 10.4067/S1726-569X2016000100006.

    [2] Inter-American Drug Abuse Control Commission [CICAD]. Report on Drug Use in the Americas 2019: Executive Summary. Tech. rep. Washington, DC, 2019. URL: http://www.cicad.oas.org/cicaddocs/Document.aspx?Id=4976.

    [3] OECD and World Bank. Health at a Glance: Latin America and the Caribbean 2023. 2023. DOI: https://doi.org/10.1787/532b0e2d-en. URL: https://www.oecd-ilibrary.org/content/publication/532b0e2d-en.

    [4] Servicio Nacional para la Prevención y Rehabilitación del Consumo de Drogas y Alcohol [SENDA]. Décimo Cuarto Estudio Nacional de Drogas en Población General de Chile, 2020. Tech. rep. Santiago, Chile: Ministerio del Interior y Seguridad Pública, 2022. URL: https://www.senda.gob.cl/wp-content/uploads/2022/01/Estudio-PG2020.pdf.

    [5] M. Mateo-Pinones, A. González-Santa Cruz, R. Portilla Huidobro, et al. “Evidence-based policymaking: Lessons from the Chilean Substance Use Treatment Policy”. In: International Journal of Drug Policy 109 (nov.. 2022), p. 103860. ISSN: 0955-3959. DOI: 10.1016/j.drugpo.2022.103860. URL: https://www.sciencedirect.com/science/article/pii/S0955395922002766.

    [6] Instituto Nacional de Estadísticas [INE]. Tablas de Mortalidad de Chile 1992-2050: Documento Metodológico. ene.. 2023. URL: https://www.ine.gob.cl/docs/default-source/proyecciones-de-poblacion/metodologia/proyecci%C3%B3n-base-2017/tablas-de-mortalidad-de-chile-1992-2050-metodologia.pdf?sfvrsn=ff4b0f8a_5}.

    [7] M. Szklo and F. J. Nieto. Epidemiology : beyond the basics. Fourth edition. Burlington, Mass: Jones & Bartlett Learning, 2019. ISBN: 978-1-4496-0469-1.

    [8] Ã. Castillo-Carniglia, J. S. Kaufman, and P. Pino. “Geographical distribution of alcohol-attributable mortality in Chile: A Bayesian spatial analysis”. In: Addictive Behaviors 42 (mar.. 2015), p. 207–215. ISSN: 0306-4603. DOI: 10.1016/j.addbeh.2014.11.025. URL: http://dx.doi.org/10.1016/j.addbeh.2014.11.025.

    [9] F. Mascayano, T. Tapia, S. Schilling, et al. “Stigma toward mental illness in Latin America and the Caribbean: a systematic review”. In: Revista Brasileira de Psiquiatria 38.1 (mar.. 2016), p. 73–85. ISSN: 1516-4446. DOI: 10.1590/1516-4446-2015-1652. URL: http://dx.doi.org/10.1590/1516-4446-2015-1652.

    [10] J. C. Sapag, B. F. Sena, I. V. Bustamante, et al. “Stigma towards mental illness and substance use issues in primary health care: Challenges and opportunities for Latin America”. In: Global Public Health 13.10 (ago.. 2017), p. 1468–1480. ISSN: 1744-1706. DOI: 10.1080/17441692.2017.1356347. URL: http://dx.doi.org/10.1080/17441692.2017.1356347.

    Funding sources

    • This work was funded by ANID - Millennium Science Initiative Program - N° NCS2021_003 (Castillo-Carniglia) and ANID - Doctoral Scholarship National Doctorate/2023-21230172 (González-Santa Cruz)

    • Correspondence to: Andrés González-Santa Cruz,

    High mortality in SUT Patients, particularly among women, and regional variations in mortality risks